domestic ventilation compliance guide 2010

7/27/2019 Domestic Ventilation Compliance Guide 2010

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Domestic VentilationCompliance Guide

2010 Edition


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April 2010Department for Communities and Local Government

Domestic Ventilation Compliance Guide2010 Edition


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Published by NBS, part of RIBA Enterprises Ltd, and available from:

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Contents | 3

Contents

Section 1 Introduction 5 1.1 Status of guide 5

1.2 Requirements on air flow testing, commissioning andinformation provision 6

1.3 How to use this guide 7

1.4 Key terms 8

Section 2 Natural ventilation and intermittent extract systems 9

2.1 System 1 Background ventilators and intermittent extract fans 9

2.2 System 2 Passive stack ventilation 9

Section 3 Continuous mechanical ventilation systems 24

3.1 System 3 Continuous mechanical extract: centralised andde-centralised 24

3.2 System 4 Continuous mechanical balanced systems with heatrecovery: centralised and single room 24

Section 4 System completion and handover 53

4.1 Documentation to be handed over to the end user 53

Section 5 Inspection checklist and air flow measurement test sheet 55

5.1 Checking design against measured air flow rates 55

5.2 Instrument calibration 56

5.3 Demonstrating compliance 56

Part 1 System details and declarations 57

Part 2a Installation details 58

Part 2b Inspection of installation 59 Part 3 Air flow measurement test and commissioning details 61


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Section 1 Introduction | 5

Section 1

Introduction

This guide provides detailed guidance to help persons comply with requirements in

building regulations for installation, inspection, testing, commissioning and provision of

information when installing fixed ventilation systems in new and existing dwellings. The

aim is to ensure the provision of adequate ventilation while minimising energy use and

environmental problems such as noise and thermal discomfort.

It is important to note that the guide covers a range of frequently occurring

situations but it is not exhaustive and alternative means of achieving compliance

with the ventilation requirements in the Building Regulations may be possible.

1.1 Status of guide

Building regulations contain functional requirements, such as requirements that buildings

must be structurally stable, must be constructed and fitted out to ensure reasonable levels

of fire protection, and must be reasonably energy efficient. These functional requirements

are often drafted in broad terms, and so it may not always be immediately clear to a person

carrying out building work how to comply with the relevant requirements. Consequently

documents are often issued by the government department responsible for building

regulations which provide practical guidance on ways of complying with specific aspects

of building regulations in some of the more common building situations. In England and

Wales, these documents are called Approved Documents.

Approved Documents are intended to provide practical guidance but they are not intended

to be comprehensive. Consequently there may be references in Approved Documents to

other documents which will provide more detailed information and assistance on parts ofthe guidance. This guide is one of those documents. It provides additional detail in relation

to the guidance about compliance with the requirements for installation, inspection,

testing, commissioning and provision of information in Approved Documents F, L1A and

L1B which apply when installing fixed ventilation systems in new and existing dwellings.


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6 | Domestic Ventilation Compliance Guide: 2010 Edition

It is important to note that following the guidance in an Approved Document or any

guidance referred to by that document does not guarantee compliance with building

regulations. If you follow relevant guidance in an Approved Document and in any

document referred to which provides additional advice or information to help you followthat guidance (such as this guide), there is a legal presumption that you have complied with

building regulations. However, in every case it is for the building control body, whether a

private sector approved inspector or the local authority, to decide whether work complies

with building regulations. So, you should always check with the building control body

before you start work what they consider it is necessary for you to do to comply with

building regulations.

1.2 Requirements on air flow testing, commissioning andinformation provision

In England and Wales, requirements for ventilation and energy efficiency are contained in

Part F, Ventilation, and Part L, Conservation of fuel and power, of Schedule 1 to the Building

Regulations. This guide provides appropriate guidance for the four types of ventilation

system discussed in detail in Approved Document F. It is referenced by Approved Document

F (ADF), Approved Document L1A (ADL1A), and Approved Document L1B (ADL1B) as

providing guidance on meeting those requirements for ventilation systems.

Specific statutory requirements in the Building Regulations for England and Wales which

this guide addresses are:

The requirement to commission mechanical ventilation systems (where they

can be tested and adjusted) in accordance with an approved procedure, and

to provide a notice confirming that commissioning has been carried out to the

building control body not later than five days after the work has been completed

where a person has had to submit a building notice or full plans or, in other cases,

not later than 30 days after the completion of work.

For mechanical ventilation systems in new dwellings only, the requirement

to measure air flow rates in accordance with an approved procedure, and to

provide a notice recording the results and the data on which they are based in an

approved manner to the building control body not later than five days after the

final test is carried out.

The requirement to provide sufficient information about the ventilation system

and its maintenance requirements to owners or occupiers so that the ventilation

system can be operated to provide adequate air flow. This guide contains

recommendations on the range of information that could be given to dwelling

owners on completion to satisfy this requirement.


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Section 1 Introduction | 7

The approved procedures for commissioning mechanical ventilation systems in

dwellings and air flow testing of such systems in new dwellings are set out in

Tables 2, 6 and 8 according to which ventilation system has been adopted.

The manner in which the results of air flow testing and the data on which they

are based are to be recorded and given to the building control body is given in

Part 3 of Section 5 of this document. A downloadable copy of this form is available at

www.planningportal.gov.uk/approveddocuments >Part F (Ventilation)>Associated

documents, for the use of those carrying out the air flow testing.

In addition to specifying how the above statutory requirements in the Building Regulations

should be met, this guide also contains recommendations for an inspection checklist and

for recording the equivalent area of background ventilators.

The inspection checklist and air flow measurement test and commissioning sheet in

Section 5 should be completed by installers and test and commissioning engineers,

and should form part of the information pack given to dwelling owners to satisfy the

information requirement.

1.3 How to use this guide

The guide refers to Systems 1 to 4 as specified in Approved Document F.

Section 2provides guidance on installation, inspection and testing of natural ventilation

and intermittent extract systems; andSection 3provides guidance on installation,

inspection, testing and commissioning of continuous mechanical ventilation systems.

The testing and commissioning procedures set out in this guide are the approved methods

by which a system must be checked and assessed before handover to the end user. For

mechanical ventilation (both intermittent and continuous), air flow measurement tests

are included as part of the commissioning process. For natural ventilation openings, the

recommendation is to carry out a visual inspection and record theequivalent area.

Supplementary information appears in some places in the guide initalic font with a grey

background. It is intended to assist understanding of the guidance or to direct readers

to sources of additional information, but is not part of the guidance. In some cases

there are links to best practice guidance that goes beyond the recommended minimum

requirements.

BS EN 14134: 2004Ventilation for buildings Performance testing and installation checks

of residential ventilationsystemsmay be referred to for further guidance on installation,inspection, testing and commissioning procedures.


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Section 4details the information that it is recommended should be left with the building

owner on completion of the installation of the system. This information is to aid the user to

correctly operate and maintain the system.

Section 5contains in Part 1 a form for recording details of the installation; in Part 2a

an installation checklist; in Part 2b a form for recording the results of a visual inspection

of the installation; and in Part 3 the air flow measurement test and commissioning

sheet to be given to the building control body.

1.4 Key terms

The following key terms where used in this guide are shown inbold italicfont. For other

terms, reference should be made to Approved Document F.

Background ventilatoris a small ventilation opening designed to provide controllable

whole building ventilation.

BCB or building control bodyis a local authority or an approved inspector.

Continuous mechanical extract ventilation (MEV)is a ventilation system comprising

a central ducted continuously running extract fan (or a set of local continuously running

extract fans in the wet rooms for de-centralised systems), air being supplied via background

ventilators into the habitable rooms.

Continuous mechanical balanced ventilation with heat recovery (MVHR)is a

ventilation system that comprises central ducted supply and extract fans, air being supplied

into the habitable rooms via a heat recovery unit.

Equivalent areais a measure of the aerodynamic performance of a ventilator. It is the area

of a sharp-edged circular orifice which air would pass through at the same volume flow

rate, under an identical applied pressure difference, as the opening under consideration.

Free areais the geometric open area of a ventilator or terminal.

Intermittent extract fanis a mechanical ventilator that does not run all the time, usually

only running when there is a particular need to remove pollutants or water vapour (e.g.

during cooking or bathing). Intermittent operation may be under either manual control or

automatic control.

Passive stack ventilation (PSV)is a ventilation system using ducts from terminals in the

ceilings of rooms to terminals on the roof that extract air to outside by a combination of the

natural stack effect and the pressure effects of wind passing over the roof of the building.

Single room heat recovery ventilator (SRHRV)is a ventilation system comprising localcontinuously running balanced supply and extract fans in a single room.


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Section 2 Natural ventilation and intermittent extract systems | 9

Section 2

Natural ventilation and intermittentextract systems

2.1 System 1 Background ventilators and intermittentextract fans

The information provided in Tables 1 and 2 gives guidance on good installation practiceand on procedures for the inspection and air flow measurement testing of systems

comprisingbackground ventilatorsand intermittent extract fans(including cooker

hoods) for dwellings. The relevant design guidance is given in ADF, in particular Table 5.2a.

2.2 System 2 Passive stack ventilation

The information provided in Tables 3 and 4 gives guidance on good installation practice

and the procedures for the inspection of passive stack systems for dwellings. The relevant

design guidance is given in ADF, in particular Table 5.2b.

Note:

If intermittent extract fans are installed in dwellings where the ventilation system

follows System 2, air flow measurement testing should be carried out and recorded as

for System 1.


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Table1:System1installationguidelines

Installationclause

s

Supplementaryinformation

1.0Intermittent

extract

fans

(including

cooker

hoods)

Manufacturersde

tailsandspecificinstruction

s

a.

Theinformation

providedinthisTablesetsouttheminimumrecommended

proceduresforty

picalSystem1installations.

b.

Forfurtherprodu

ct-specificinformation,refertothemanufacturers

installationinstru

ctions.

Preparation

a.

Ensurethefinallocationofequipmentofferssufficientspacetoallowaccess

formaintenance

.

b.

Forthrough-wallunits,coreaholeofasuitabledimensionthroughthe

fabricofthebuildingfortheinstallationofthed

uct.T

heholeshouldhavea

slightdownward

angletowardstheoutsidetop

reventwateringress.

c.Forceilingmoun

tedfans/terminals,t

heholessh

ouldbecuttotheminimum

requiredsizesuchthatthefan/grillespigotfitssnuglyintothehole.

d.

Whereductwork

penetratesabuildingsairbarrier,thecontinuityofthe

barriermustbem

aintained.T

henatureofthebarrierandeaseofachieving

aneffectivesealshouldbeconsideredbeforeho

lesaredrilled.

e.

Itisimportantto

considertheplanningandinstallationofductworkinco-

ordinationwitho

thertradeactivitiesandinstallations,suchthatroutesare

designedwithou

tcompromisetotherequiredv

entilationairflowrates.

Installationthroughwall

a.

Theductsleevec

onnectingthefanoutlettothe

terminal/grilleshouldbeat

leastthesamediameterasthefanoutlet.

b.

Theductsleeves

houldberigid.Insituationswh

erethisisnotpossible,

flexibleductworkmaybeused,providingextrac

tventilationratesarenot

compromised.Flexibleductworkshouldbepulledtaut.

c.Theinstalledduc

tsleeveshouldbesealedtothe

externalandinternalwallto

maintainairtightness.T

hisisofparticularimportanceforcavitywalls.

d.

Ensurethatthere

arenoobstructionsintheductpriortofittingthefan.


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Table1:System1installationguidelines(continued)

Installationclause

s


1.0Intermittent

extract

fans

(including

cooker

hoods)

(continued)

Installationthroughwindow

a.

Checkthesuitab

ilityofthewindowandobtainasuitablewindowmounting

kitfromtheman

ufacturerfortheproposedfan

unit.

Forwindowmountedfans,do

not

plantoinstallinopeninglights.T

he

minimumadvisableglassthicknessis

4mm,butseekspecialistadvicefrom

glazierformountingsuitability.

Installationducted

a.

Rigidducts,recta

ngularorcircular,shouldbeusedwhereverpossible.W

here

necessary,flexibleductsmaybeused,buttheirlengthsshouldbekepttoa

minimum,conne

ctingtorigidductworkatthee

arliestopportunity.

b.

Forflexibleductconnectedtoaxialfanstheleng

thislimitedto1.5metres;

forcentrifugalfa

nsthelengthlimitis6metres(forextractrates6to30l/s),

and3metres(forextractrates31to60l/s).

c.Thenumberofb

endsislimitedtotwoforupto

30l/s,andreducestoone

bendforhigherextractrates.

d.

Flexibleductshouldbepulledtaughttoensurethatthefullinternal

diameterisobtainedandflowresistanceminimised.T

hisisconsideredto

havebeenachievediftheductisextendedto90

%o

fitsmaximumlength.

e.

Ductingshouldb

einsulatedwhereitpassesthroughunheatedareasand

voids(e.g.loftsp

aces)withtheequivalentofatleast25mmofamaterial

havingathermalconductivityof0.0

4W/(m.K

)toreducethepossibilityof

condensationforming.

f.Horizontalducting,includingductinginwalls,shouldbearrangedtoslope

slightlydownwardsawayfromthefantopreventbackflowofanymoisture

intotheproduct.

g.

Verticalductingwill

requireacondensatetrapin

ordertoprevent

backflowofanymoistureintotheproduct.Follo

wthemanufacturers

recommendationsintheseinstances.

h.

Whereductingp

assesthroughafire-stoppingw

allorfirecompartment,

therequiredmea

surestoensurecompliancewithPartBoftheBuilding

Regulationsshou

ldbetaken.

Exceptionstoductlimitswillbe

acceptedprovidingevidencefrom

themanufacturerisavailable

thatconfirmsthatthespecified

performancewilln

otbeaffected.

Forin-linefans,referto

manufacturersdata.

Forductinstallations,seeDiagram1.

Wherepossible,connectstraig

ht

lengthsofductworktofanspigot.


13/64



Installationclause

s


Cookerhoods

a.

Cookerhoodssh

ouldbeinstalledsothataccess

iseasyforchangingand

cleaningofthefi

lter/filters.

Re-circulatingcookerhoodsdo

not

provideextractventilation.Toprovide

extractventilationinakitchenfor

thepurposesofPartF,anextractfan

tooutsideshouldhaveaninsta

lled

capacityofatleast60l/s.

2.0Ventilation

airinletsand

discharge

terminals/

grilles

Backgroundventilators

a.

Backgroundventilatorsshouldbeprovidedtom

eettheminimumrequired

equivalentareao

fventilationspecifiedbyTable

5.2aofADF.

b.

Forwallmountedbackgroundventilatorsmake

anopeninginthewall

inaccordancewiththemanufacturersinstructionsforthesizerequired.

Ensurethatthere

arenoobstructionsintheopening.

c.Installthewallor

windowventilatorproductinaccordancewiththe

manufacturersinstructions.

d.

Ensurethatwallorwindowventilatorproductsaresealedtotheirsurrounds

usingaproprieta

rysealantasrecommendedby

themanufacturer.

Backgroundventilatorsfittedin

windowsareusuallyinstalledd

uring

manufacture.C

loseco-ordination

betweensupplierandinstalleris

recommendedtoensurecorrect

locationofventilators.

Backgroundventilatorsinstalle

din

wallsmayrequireaproprietary

wind

cowltoreducewindnoiseand

prevent

over-ventilation.

Dischargetermina

ls/grillesroofandwallmo

unted

a.

Onlyproprietary

terminalsshouldbeused.

b.

Ensurethatthefreeareaoftheterminal/grilleopeningisaminimumof

90percentofthefreeareaoftheductingbeing

used.


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Installationclause

s


3.0Miscellaneous

Airtransfer

a.

Toensuregoodtransferofairthroughoutthedwelling,t

hereshouldbean

undercutofminimumarea7600mm

2in

allinternaldoorsabovethefloor

finish.T

hisisequ

ivalenttoanundercutof10mmforastandard760mm

widthdoor.

b.

Ensurethatthea

irtransferprovisionisunrestrictedafterfloorfinisheshave

beenlaid(e.g.ca

rpetsshouldnotencroach).Thisshouldbeachievedby

makinganundercutof10mmabovethefloorfi

nishifthefloorfinishis

fitted,orbya20

mmundercutabovethefloorb

oards,orothersurface,i

f

thefinishhasnotbeenfitted.

4.0Controls

General

a.

RefertoTable5.2aofADF.

b.

Ensurethatalocalmanualoverridecontrolisprovidedforanyextractfan

operatedbyauto

maticcontrols.

Humiditycontrolsshouldnotb

eused

forsanitaryaccommodationw

here

odouristhemainpollutant.


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Diagram 1: Duct installations

Airflow

Airflow

Room terminal/extract grille

CavitySealant

Discharge grill

Grille

discharge

opening

Maximum length of

flexible ducting

Flexible

ducting supports

-

-

Minimum radius =

the diameter of

flexible ducting used

Sleeve

Do

Dont

Preferred flexible

ducting route

Restrictions

Peaks and troughs

b

a

The inner radius of any bend should be greater or equal to the diameter of the ducting

being used. If the radius is reduced, the resistance of the bend will increase and the volume

of air being extracted will decrease (see Do diagram above).

Ensure flexible ducting is installed without peaks or troughs (see Dont diagram above).


16/64


Table2:System1inspectionandtesting

Recommendationsandminimumrequirements


1.0Intermittent

extract

fans

(including

cooker

hoods)

Visualinspections

CarryoutthefollowingchecksandrecordtheresultsinSection5:

a.

Doesthesystem

installationcomplywiththeins

tallationclausesinTable1?

b.

Doesthenumbe

rofextractpointsandterminalssatisfyTable5.2ainADF?

c.Isallequipmentingoodconditionwithnoobviousdefectsthatwill

be

hazardousoraffectthesystemperformance?

Functionalchecks

a.

Temporaryprote

ctionandpackagingshouldbe

removedfromallproducts.

b.

Checkfanoperatescorrectlywhenactivatedby

manualcontrol(e.g.l

ight

switch),orautom

aticcontrol(e.g.P

IR).

c.Ensurefanswitchesoffaftercontrolsarede-activatedand,inthecaseof

run-ontimers,th

atthesearesettoaminimumof15minutes.

Unlessthetimercontrolisgrad

uated

inminutes,run-ontimersshou

ldbe

checkedagainstatimedtestand

adjustedifruntimeislessthan

15

minutes.

Airflowmeasurem

enttesting

a.

Ensurethatallintendedbackgroundventilators

orotherairtransferdevices

areopen.

b.

Ensureallinterna

landexternaldoorsandwindowsareclosed,including

roomsinwhichm

easurementsarebeingcarried

out.

c.Airflowmeasure

mentsshouldbeperformedusingacalibratedairflow

devicewithprop

rietaryhoodattachmentandre

sultsrecordedinlitresper

second(l/s).Refe

renceshouldbemadetoTable

5.1aofADFfordesignair

flowrates.

d.

Recordtheextractairflowforeachextractfano

ntothecommissioning

sheet(seeSection5).

e.

Theinstruments

houldbecalibratedannuallyan

dbecapableofachieving

anaccuracyof

5percent.

Note:Thisistheapproved

procedureformeasuringth

eair

flowofintermittentextractfans

andcookerhoodsasrequiredby

theBuildingRegulations.

Themostcommonmethodisthe

useofavaneanemometer,orsimilar,

placedinahoodwhichcoversthe

terminalto

measuretheextractair

flowrate.

Calibrationofmeasurement

equipmentshouldbeundertaken

annuallybyreturningtheinstrument

toaUKASaccreditedcalibratio

n

centre.


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Table2:System1inspectionandtesting(continued)

2.0Background

ventilators

Visualinspections


a.

DoestheequivalentareaandlocationofairinletssatisfyTable5.2ainADF?

b.

Hastemporaryprotectionandpackagingbeenremovedfromall

backgroundventilators,anddotheshuttersopenandclosecorrectly?

c.Isthereanadequ

atesealbetweentheventilatorproductandthewall/

windowframe?

Theequivalentareashouldbe

displayedontheairinletprodu

ct.


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Installationclause

s


1.0Ductwo

rk

prepara

tion

and

installa

tion

Manufacturersde


s

a.

Theinformation


proceduresforty


b.

Forfurtherprodu


installationinstru

ctions.

c.Internalductdiametersand/orcrosssectionalareasshouldbenolessthan

thesizesgivenin

ADF,Table5.2

b.

Preparation

a.

Ductingroutesandoffsetsshouldbeplannedsuchthattheirfinal

installationisina

ccordancewiththeillustratedguidancegiveninDiagrams

2and3.

b.

Separateductsshouldbetakenfromtheceiling

softhekitchen,bathroom,

utilityroomorW

Ctoseparateterminalsontheroof.Donotusecommon

outletterminalsorbranchedducts.

c.Whereductwork


barriermustbem

aintained.T



lesaredrilled.

d.

Itisimportantto


ordinationwitho


designedwithou



Ideally,a

llductsshouldbeinsta

lledas

nearverticala

ssiteconstraintsallow.

Bothrigidductingandflexibleducting

aresuitableforPSVsystemsandhave

similarresistancetoairflowattypical

PSVsystemairflowrates.


19/64



Installationclause

s


1.0Ductwo

rk

prepara

tion

and

installa

tion

(continued)

Installation

a.

Carefullymeasurethelengthofducttobeused

suchthatitisjustsufficient

tofitbetweenth

eceilingterminalandtheoutle

tterminal.Flexibleducting

shouldbefullyextendedbutnottaut,allowingapproximately300mmextra

tomakesmooth

bendsinanoffsetsystem.

b.

Ductingshouldb

eproperlysupportedalongits

lengthtoensurethatthe

ductcanrunstra

ightwithoutdistortionorsaggingandthatthereare

nokinksatanyb

endsortheconnectionstoceilingterminalsandoutlet

terminals.F

lexibleductinggenerallyrequiresmo

resupportthanrigid

ducting.

c.Intheroofspace

theductshouldbesecuredtoawoodenstrutthatis

securelyfixedatbothends.Aflexibleductshouldbeallowedtocurvegently

ateachendofth

estruttoattachtotheceilingterminalandroofoutlet

terminal.

d.

Arigidductshou

ldbeusedforsystemstabilityforthepartofaPSVsystem

whichisoutside,

abovetheroofslope.I

tshould

projectdownintotheroof

spacefarenoughtoallowfirmsupport.

e.

Ensurethatthed

uctissecurelyfixedtotheroof

outletterminalsothatit

cannotsagorbe

comedetached.

f.Ductingshouldb


voids(e.g.loftsp



4W/(m.K


condensationforming.

g.

Whereaductextendsexternallyaboveroofleve

lthesectionabovetheroof

shouldbeinsulatedoracondensatetrapshould

befittedjustbelowroof

level.


20/64



2.0Ventilation

airinletsand

discharge

terminals


a.



equivalentareao


5.2

bofADF.

b.


anopeninginthewall


Ensurethatthere


c.Installthewallor



d.


usingaproprieta


themanufacturer.

Backgroundventilatorsfittedin

windowsareusuallyinstalledd

uring

manufacture.C

loseco-ordination

betweensupplierandinstalleris

recommendedtoensurecorrect

locationofventilators.

Backgroundventilatorsinstalle

din

wallsmayrequireaproprietary

wind

cowltoreducewindnoiseand

prevent

overventilation.

Extractterminals

wallandceilingmounted

a.

PSVextractterminalsshouldbelocatedintheceilingoronawalllessthan

400mmbelowtheceiling.

b.

Theextractterminalshouldhaveafreeareaofn

otlessthantheductcross-

sectionalarea.If

aconversionfittingisrequiredtoconnecttheductto

theterminalthen

theductcross-sectionalareas

houldbemaintained(or

exceeded)throughouttheconversionfittingso

asnottorestricttheflow.

Innon-sanitaryaccommodatio

n,

humiditycontrolledterminalsmaybe

usedtoincreasetheairflowdu

ring

periodsofincreasedhumidity,and

toreducetheairflowduringperiods

oflowhumidity.Humiditycontrols

shouldnotbeusedforsanitary

accommodationwhereodouristhe

mainpollutant.


21/64



Installationclause

s


2.0Ventilation

airinletsand

discharge

terminals

(continued)

Dischargetermina

ls

a.

ProprietaryproductsshouldbeusedthatarecompatiblewiththePSVduct

systemthathasb

eeninstalled.

b.

Therooftermina

lshouldnotallowingressoflar

geinsectsorbirdsand

shouldbedesign

edsothatrainisnotlikelytoen

tertheductandrundown

intothedwelling

.

c.Theterminalsho

uldalsobedesignedsuchthatanycondensationforming

insideitcannotrundownintothedwellingbutwill

runoffexternallyonto

theroof.

d.

Atileventilatoru

sedtoterminateaPSVsystemontheroofslopeshouldbe

positionednomorethan0.5mfromtheroofrid

ge.I

ftheductpenetrates

theroofmorethan0.5mfromtheridge,i

tshou

ldextendabovetheroof

slopetoatleastr

idgeheight.

RefertoDiagram2forfurtherdetails.

3.0Miscellaneous

Airtransfer

a.


hereshouldbean


2in


finish.T

hisisequ


widthdoor.

b.

Ensurethatthea


beenlaid(e.g.ca




fitted,orbya20



f



22/64


Table4:System2inspection

Recommendedmi

nimumrequirements


1.0Ductwo

rkand

terminals

Visualinspections


a.

Doesthesystem



b.

Doesthenumbe

randsizeofterminalpointssat

isfyTable5.2

binADF?

c.Isallductworkandareallterminalsingoodconditionwithnoobvious

defectsthatwillbehazardousoraffectsystemp

erformance?

2.0Background

ventilators

Visualinspections


a.

Doesthesize,nu

mber,orientationandlocation

ofairinletssatisfyTable5.2

b

inADF?

b.

Hasanytempora

ryprotectionandpackagingbeenremovedfromall

backgroundventilators,anddoshuttersopenandclosecorrectly?

c.Isthereanadequ

atesealbetweentheventilatorproductandthewall/

windowframe?

Theequivalentareashouldbe

displayedonthebackground

ventilatorproduct.


23/64


Diagram 2: Suitable layouts for PSV systems

The layouts shown in Diagram 2 are considered to be suitable for the majority of dwellings

of up to four storeys. Placing the outlet terminal at the ridge of the roof (Diagram 2(a)) is the

preferred option for reducing the adverse effects of wind gusts and certain wind directions.

A tile ventilator may be used to terminate aPSVsystem on the roof slope but the terminal

should be positioned no more than 0.5 m from the roof ridge. If the duct penetrates the

roof more than 0.5 m from the ridge, it should extend above the roof slope to at least ridge

height to ensure that the duct terminal is in the negative pressure region above the roof

(Diagram 2(b)).


24/64


Diagram 3: Suitable and unsuitable bends for passive stack ducts

Ducts should use no more than one offset (i.e. no more than two bends) and these shouldbe of the swept rather than sharp type to minimise flow resistance. Offsets at an

angle should be no more than 45 to the vertical (Diagram 3).


25/64


Section 3

Continuous mechanical ventilationsystems

3.1 System 3 Continuous mechanical extract: centralisedand de-centralised

The information provided in Tables 5 and 6 gives guidance on good installation practiceand the procedures for the inspection, air flow measurement testing and commissioning of

continuous mechanical extract ventilation(MEV) systems for dwellings. The relevant

design guidance is given in ADF, in particular, Table 5.2c.

3.2 System 4 Continuous mechanical balanced systemswith heat recovery: centralised and single room

The information provided in Tables 7 and 8 gives guidance on good installation practice

and the procedures for the inspection, air flow measurement testing and commissioning

of continuous mechanical balanced ventilation with heat recovery(MVHR) systems

for dwellings. The relevant design guidance is given in ADF, in particular, Table 5.2d. The

installation and inspection guidance is also suitable forsingle room heat recovery

ventilators(SRHRV).


26/64

Section 3 Continuous mechanical ventilation systems | 25


Installationclause

s


1.0Continu

ous

extract

fans:

centralised

Continu

ous

extract

fans:

decentralised

Manufacturersde


s

a.

Theinformation


proceduresforty


b.

Forfurtherprodu


installationinstru

ctions.

c.Thesuitabilityof

connectionofacontinuousfan

systemtoacookerhood

mustfollowthemanufacturersguidance.

Locationoffanun

it

a.

Thefanunitshouldbelocatedinaccordancewiththemanufacturers

specifications.

b.

Ensurethefinallocationofequipmentofferssufficientspacetoallowaccess

formaintenance

.

c.Thefanunitshouldbeinstalledtoallowsufficientspaceforendoflife

replacementofthewholeunitorkeymechanical/electricalcomponents.

Thisshouldbeac

hievablewithouttheneedtoremovefixedstructuresor

significantlengthsofconnectedductwork.

d.

Thefanunitshouldbeinstalledonasoundstructure,w

hichisstableand

level.

Thelocationofthefanunitsho

uld

bechosentominimiseoverallduct

runlength,bothfromtheinternal

extractterminals/grillestothefanunit

andfromthefanunittotheexternal

dischargeterminal.

Unconditionedspaces,e.g.lof

ts,

maybecomeveryhotinsumm

er,

whichmayhaveimplicationsforboth

mechanicalandelectroniccom

ponent

life.Refertothemanufacturers

specificationforappropriate

environmentalconditions.

Thefanunitspigotarrangement

maydictatethelocationand

orientationofinstallation:toensure

optimumperformancereferto

the


Ifafanunitisinstalledinanunheated

space,itmayneedtobeinsulated

tominimisetheriskofcondensation

formingwithinthefanunitcas

ing.


27/64



Installationclause

s


1.0Continu

ous

extract

fans:

centralised

Continu

ous

extract

fans:

decentralised

(continued)

Preparationforinstallation

a.

Aholeofasuitab

ledimensionthroughthefabricofthebuildingwill

berequiredfortheinstallationoftheduct.T

heholewill

needaslight

downwardangle

towardstheoutsidetopreven

twateringress.

b.

Whereductwork


barriermustbem

aintained.T



lesaredrilled.

c.Forceilingmoun

tedfansorterminals/grilles,theholesshouldbecuttothe

minimumrequiredsizesuchthatthefan/grillesp

igotfitssnuglyintothehole.

d.

Itisimportantto


ordinationwitho


designedwithou



Installation

a.

Thefanunitshouldbeinstalledusingthemanufacturerssuppliedor

recommendedfi

xingbrackets.

Acoustic/anti-vibrationisolation

mayberequired.Thiswilld

epe

nd

onthenatureofthemounting

structure:refertothemanufac

turers

instructions.


28/64



Installationclause

s


2.0Ductwo

rk

Ductinstallation

generalnotes

a.

Ductsshouldbesizedtominimisepressurelossandnoisegeneration.T

hisis

achievedbysizin

goftheductstolimittheairvelocity.

b.

Theroutingofductsshouldminimiseoverallductlengthandminimisethe

numberofbendsrequired.I

tisparticularlyimpo

rtanttominimisebendsin

mainductsoperatingathigherairvelocities.

c.Theneedforpriv

acy(acousticseparation)betweenroomsshouldbe

consideredwhen

planningductlayout.

d.

Whereroomairextractterminals/grillesarenotfittedwithfilters,sufficient

spacetoallowac

cessforcleaningductsshouldbeprovided.

e.

Ductingshouldb


voids(e.g.loftsp



4W/(m.K


condensationforming.W

hereaductextendsaboverooflevelthesection

abovetheroofshouldbeinsulatedoracondensatetrapshouldbefittedjust

belowrooflevel.

f.Horizontalducting,includingductinginwalls,shouldbearrangedtoslope


intotheproduct.

g.

Verticalductingwill


ordertopreventbackflow

ofanymoistureintotheproduct.

h.

Perforatedinsula

tedflexid

uct,usedtominimiseairborneacoustic

transmission,shouldnotbeusedbetweenthefanunitandexternal

dischargetermin

altopreventcondensationocc

urringwithintheinsulation

material.

i.

Whereductspas

sthroughfirebarriers,t

heymu

stbeappropriatelyfire

stoppedinaccordancewiththerequirementsofPartBoftheBuilding

Regulations(Fire

Safety).

Theductsizeandtypespecifiedby

thesystemdesignershouldalw

aysbe

used,tominimisepressureloss

and

noisegeneration.Mainductsshould

berunatthesamesizeasthefan

unitspigot.Ductsizeshouldth

enbe

reducedforbranchducts.

Aradialla

youtmayachieveacoustic

separationmoreeffectivelytha

na

branchedlayout.

Theperformanceoftheventila

tion

systemreliesonefficientair

distributionanditisvitalthatduct

installationisnotleftuntilthelast

momentwhentheonlymeans

of

overcomingobstructionsistoinstall

flexibleductswhererigidductshad

beenspecified.


29/64



Installationclause

s


2.0Ductwo

rk

(continued)

Installationofductsrigid

a.

Ductsshouldnotbeinstalledwheretheycanbe

easilydamaged,for

exampleacrosso

penloftareaswheretheymay

bestoodonorhaveitems

placedonthem,

breakingsealsandpossiblycru

shingtheduct.

b.

Connectionofcomponentsshouldnotresultin

significantairflow

resistance.Componentsshouldbeproprietarya

ndfiteasilytogether

withoutdistortio

n.

c.Rigidductrunsm

ustbeadequatelysupported.

Distortionofrectangularductmay

resultinsignificantreductiono

f

thefreeinternala

reaoftheduct,

increasingtheflowresistanceand

makingsealingmoredifficult.

Installationofductsflexible

a.


easilydamaged,for

exampleacrosso

penloftareaswheretheymay

bestoodonorhaveitems

placedonthem,

crushingtheductandrestrictin

gorpreventingallairflow

throughtheduct.

b.

Flexibleductshouldbepulledtaughttoensurethatthefullinternal

diameterisobtainedandflowresistanceminimised.T

hisisconsideredto

havebeenachievediftheductisextendedto90

%o

fitsmaximumlength.

c.Flexibleductworkshouldbesupportedatsuitab

leintervalstominimise

sagging.

d.

Bendsinflexibleductshouldhaveaminimumin

sideradiusequaltothe

diameterofthed

uctseeDiagram1.I

ftighterbendsarerequired,r

igid

bendsshouldbe

used.

Itissuggestedthatflexibleducts

shouldbesupportedatintervalsnot

exceeding600mm.


30/64



Installationclause

s


2.0Ductwo

rk

(continued)

Ductconnections

a.

Allductconnectionsrequiresealing.W

hereduc

tsareinstalledagainsta

solidstructureth

iscanbedifficulttoachieve.In

suchlocationspreassembly

ofductsectionsshouldbeconsidered.T

hiswillrequirethatconnectionsare

permanenttoen

surethesealismaintainedduringinstallation.

b.

Whereaccessto

ductswill

notbepossibleafterconstructioniscomplete,

i.e.ductworkisw

ithinfloorandwallvoids,considerationshouldbegiven

topermanentco

nnectionandsealingwithanappropriatenon-hardening

sealant,andnotusingducttapetoachieveconnectionandsealing.

c.Connectionofle

ngthsofflexibleductmustuse

arigidconnectorandjubilee

clipsorsimilarto

ensurealongtermsealisachie

ved.Connectionsoflengths

offlexibleductshouldnotbetaped-only.

3.0Ventilation

airinletsand

interna

lair

transfer


a.



equivalentareao


5.2cofADF.

b.


anopeninginthewall


Ensurethatthere


c.Installthewallor



d.


usingaproprieta


themanufacturer.


31/64



Installationclause

s


3.0Ventilation

airinlets

andinternal

airtransfer

(continued)

Airtransfer

a.


hereshouldbean


2in


finish.T

hisisequ


widthdoor.

b.

Ensurethatthea


beenlaid(e.g.ca




fitted,orbya20



f


4.0Roome

xtract

airterm

inals/

grilles

Extractterminals/grillesgeneralnotes

a.

Allroomairextra

ctterminalsshouldbeinstalled

asdetailedbythesystem

designer.

b.

Roomairextract

terminalsshouldbeinstalledasclosetoceilinglevelas

practical,toensu

rewarmmoistairisremovedfromeachspace.

Fixedterminalsg

rillesorlouvers

a.

Iftheroomextractairterminalsarefixed,ensurethateffectivebalancingof

thesystemcanb

eachieved.I

fafacilityisnotpro

videdwithinthefanunit

thendamperssh

ouldbeinstalledwithintheductsystemtoallowbalancing

whenthesystem

iscommissioned.

Adjustabletermin

als/grilles

a.

Ensureeachterm

inal/grillecanbelockedinitscommissionedpositiononce

systembalanceh

asbeenachieved.I

tisvitalforthecorrectoperationofthe

systemthatthes

ystemremainsbalancedinitsc

ommissionedstate.


32/64



Installationclause

s


5.0Externa

l

discharge

terminal

Dischargetermina

lsroofandwallmounted

a.

Proprietaryterminalsshouldbeused.

b.

Ensurethatthefreeareaoftheterminalopeningisaminimumof90%

of

thefreeareaoftheductingbeingused.

c.Thelocationoftheexternaldischargeterminalshouldensurethatthe

potentialforrecirculationofextractairthrough

ventilationairinletsis

minimised.

6.0Controls

Controlsgeneralnotes

a.

Continuousventilationsystemsshouldnotallow

theoccupiertoturnoffthe

fanotherthanatthelocalisolator.Provisionofa

non/offfunctionwill

result

inthefansbeing

operatedintermittentlyandth

erequiredcontinuousair

flowventilationratesnotbeingachieved.

b.

Wheresensorsarenotpre-installedwithinthefanunit,oradditional

optionalsensors

canbeinstalled,onlythesenso

rsspecifiedbythe

manufacturerof

thefanunitshouldbeinstalled

.

c.Ifsensorsareduc

tmounted,t

heirlocationshou

ldbenotedandprovisionfor

accessformaintenanceorreplacementmade.

d.

Ifcontrolofthefanspeedisundertakenmanually,t

heoperationofthefan

inboostmodesh

ouldbemadeobvious.Thiswill

minimisethelikelihoodof

itbeingleftinthismodeunnecessarily.

e.

Humiditycontrolshouldnotbeusedinsanitary

accommodation,w

here

odouristhemainpollutant.

Installationofalternativesenso

rs

mayresultincontrolfunctions

not

performingcorrectly.


33/64



Installationclause

s


6.0Controls

(continued)

Controlslocation

andconfiguration

a.

Installationofmanualcontrolsforthesystemmustmeettherequirements

ofPartMoftheBuildingRegulations.

b.

Installationofroomsensorsshouldfollowthem

anufacturersguidanceon

positioning.

c.Wherecontrolofthefanspeedisundertakenm

anually,switchingshould

beprovidedlocallytothespacesbeingserved,i.e.bathroomsandkitchen.

Provisionofasinglecentrallylocatedswitchisnotsufficientandwill

resultin

fansbeingleftin

inappropriatemodesofoperation.

ApprovedDocumentM,Sectio

n8.3,

recommendsthatswitchessho

uld

belocatedbetween450mmand

1200mmfromfinishedfloorlevel.

7.0Continu

ous

extract

fans:

decentralised

In-ductinstallation

a.

Thefanunitshouldbeadequatelysupportedus

ingthemanufacturers

suppliedorrecom

mendedfixingbrackets.

b.

Accessshouldbe

providedtothefanunitformaintenanceandreplacement

attheendofitso

perationallife.


34/64


Table6:System3inspection,testingandcommissioning

Recommendedmi

nimumrequirements


1.0System

overvie

w

Visualinspections


a.

Doesthesystem



b.

Isthesysteminst

alledinaccordancewithdesign

criteria?


defectsthatwillbehazardousoraffectsystemp

erformance?

Initialstart-up

a.

Istheairflowdirectioncorrectateachroomterminal?

b.

Arethereanyabnormalnoisesonstart-uporwhenthesystemisrunningin

normalbackgrou

ndventilationmode?

Somefanunitshaveastart-up

diagnosticsequencethatrunsthe

fansatmaximumspeedforap

eriod

beforerevertingtonormalope

ration

refertothemanufacturersoperating

instructions.


35/64



Minimumrequirem

ents


2.0Commissioning:

airflow

balancingand

measur

ement

Airflowbalancing

a.

Thesystemshouldbebalancedtoensurethatdesignairflowratesare

achievedateach

roomterminal/grille.Asthereareseveralcombinationsof

roomterminal/grille(referredtoasaterminalfro

mhereon)andfancontrol

thatmaybeused

indomesticsystems,thefanm

anufacturersinstructions

shouldbefollow

edtoachievebalancing.I

fspec

ificdetailsarenotincluded

thefollowingpro

cedureshouldbeadopted:

i.

Adjustable

terminalsandafixed(stepp

ed)speedfan.

Thefanspee

dshouldbesettoachievethed

esiredcontinuousflowrate.

Theindexterminalflowrateissettofullyop

enandallothergrillesare

adjustedtoa

chievetherequiredflowsateachterminal.

Ifthetotalflo

wratecannotbeachievedthroughalltheterminalsthen

thefanspeedshouldbeincreased.

Ifalltheterm

inalshavetobeclosedsignificantlytoachieveonlythe

requiredairfl

owratethenreducethefansp

eedandrebalancethe

terminals.

ii.Adjustable

terminalsandcontrollables

peedfan.

Thefanspee

dshouldbesetapproximatelytoachievethedesired

continuousfl

owrate.

Theindexterminalflowrateissetwiththeterminalfullyopenand

allotherterm

inalsareadjustedtoachieveth

erequiredflowsateach

terminal.

Iftheindexterminalhastobeclosedtoachieveonlytherequiredair

flowrate,thenreducethefanspeedandrebalancetheterminals.


procedureforcommissionin

g

asrequiredbytheBuilding

Regulations.

Theindexterminal/grillecanbe

assumedtobetheterminalfur

thest

fromthefanunit.


36/64


Table6:System3inspection,testingandcommissioning(contin

ued)

Minimumrequirem

ents


2.0Commissioning:

airflow

balancingand

measur

ement

(continued)

iii.Fixedterminalswithflowadjustmentb

yductdamperorsimilar

deviceatth

efanunit.

Asi.orii.abo

vedependingonthetypeoffa

nspeedcontrol.

iv.Adjustable

terminalsandfixedvolume

flowfan.

Thefanspee




allotherterm



terminal.Adjustmentoftheterminalsachievesbalancingonly;total

flowrateisg

overnedbythefancontrolsetting.Greatcareshould

betakennot

toclosetheterminalstoofarasthefanunitwill

always

maintainaconstantvolumetricflowrate;closingtheterminalswill

only

requirethefantoworkhardertoachieveagivenairflowrate.

v.Fixedterminalswithautomaticflowad

justmentatthefanunit.

Thefanspee



Theflowsarebalancedbyautomaticdevice

slocatedwithinthefanunit,

andnoadjus

tmentcanbemade.


37/64



ued)

Minimumrequirem

ents


2.0Commis

sioning:

airflow

balancingand

measur

ement

(continued)

Airflowmeasurem

ents

a.

Ensurethatback

groundventilatorsorotherairtransferdevicesareopen.

b.

Ensureallinterna


roomsinwhichm


out.

c.Airflowmeasure


devicewithprop



second(l/s).Refe

renceshouldbemadetodesignairflowrates.

d.

Recordtheairflo

wrateateachroomterminalo

nthecommissioning

sheetinSection5,a

longwiththedesignairflow

rateforeachterminal.

Measurementsshouldbetakenatbothmaximu

mrateandminimumrate

fanspeeds.

e.

Itisrecommende

dthatavaneanemometerors

imilardeviceisused

tobalanceandm

easuretheairflowratesateac

hroomterminal.The

instrumentwillrequireahoodtobeattachedto

allowittocoverthe

terminal.

f.Theinstruments



anaccuracyof

5percent.


procedureforairflow

measurementasrequiredb

ythe

BuildingRegulations.

Themostcommonmethodisthe

useofavaneanemometer,orsimilar,

placedinahoodwhichcoversthe

terminalto

measuretheextractair

flowrate.





n

centre.


38/64



ued)

Recommendedmi

nimumrequirements


3.0Controls

Installation

a.

Ensurealllocalcontrolshavebeeninstalledfollo

wingthemanufacturers

instructions.

b.

Ensurealllocalcontrolsareadequatelylabelled,

indicatingtheirfunction

clearly.

c.Ifsensorshavebeeninstalledseparatelyfromth

efanunitensureinstallation

followsthemanufacturersinstructions.

d.

Wherecontrolofthefanisautomated,t

hecontrolsshouldbeconfiguredto

minimisetheocc

urrenceofhunting.

e.

Ifmanualcontrolof,forexample,heatexchang

erby-passisprovided,c

lear

anddetailedinstructionsshouldbemadeavailabletotheoccupier.

Ifhunting(thecontinualincrea

se

anddecreaseoffanspeed)does

occur,occupantsmayseektom

odify

thecontrolofthesystemorturnit

offaltogethertoremovethenoise

nuisance.

Testingoperation

a.

Asfaraspractica

lthecorrectoperationofeachcontrolfunctionshouldbe

tested.


39/64



Installationclause

s


1.0Continu

ous

supplyand

extract

with

heatrecovery:

centralised

Continu

ous

singleroom

supplyand

extract

with

heatrecovery

Manufacturersde


s

a.

Theinformation


proceduresforty


b.

Forfurtherprodu


installationinstru

ctions.

c.Thesuitabilityof

connectionofacontinuousfan

systemtoacookerhood

mustfollowthemanufacturersguidance.


40/64



Installationclause

s


1.0Continu

ous

supplyand

extract

with

heatrecovery:

centralised

Continu

ous

singleroom

supplyand

extract

with

heatrecovery

(continued)

Locationoffanun

it

a.

Thefanunitshouldbelocatedasspecifiedbyth

esystemdesigner.

b.

Fanunitsshould

beinstalledtoallowsufficientspacetoundertakeroutine

maintenanceon

filtersandheatexchangerbloc

kasappropriate.

c.Fanunitsshould

beinstalledtoallowsufficientspaceforendoflife

replacementofthewholeunitorofkeymechan

ical/electricalcomponents.

Thisshouldbeac

hievablewithouttheneedtoremovefixedstructuresor

significantlengthsofconnectedductwork.

d.

Thefanunitshouldbeinstalledonasoundstructure,w

hichisstableand

level.

e.

Ifthefanunitisn

otpre-insulated,insulationsho

uldbeaddedtominimise

theriskofcondensationformingwithin,oron,thefanunitcasing.

f.Acondensatedrainshouldbeinstalledfromthe

fanunittoanappropriate

drainlocation.Thecondensatepipeshouldbeinstalledtohaveaminimum

5fallfromthefanunit.

g.

Thecondensatedrainshouldbeadequatelysecuredandwherepassing

throughanunhe

atedspacemustbeadequatelyinsulatedtoprevent

freezing.

AdditionalnotesforSRHRV

a.

Donotinstallthe

unitinthecornerofaroomas

thismayresultinshort

circuitingofairfl

ows.

Thelocationofthefanunitsho

uld

bechosentominimiseoverallduct

runlength,bothfromtheinternal

terminals/grillestothefanunit

and

fromthefanunittotheexternal

dischargeterminal.

Unconditionedspaces,e.g.lof

ts,

maybecomeveryhotinsumm

er,

whichmayhaveimplicationsforboth

mechanicalandelectroniccom

ponent

liferefertothemanufacturers

specificationforappropriate

environmentalconditions.

Thefanunitspigotarrangement

maydictatethelocationand

orientationofinstallation:toensure

optimumperformancereferto

the


Therateofcondensateformationmay

beuptoseverallitresperday,a

ndthis

shouldbeconsideredwhenchoosing

thedrainlocation.


41/64



Installationclause

s


1.0Continu

ous

supplyand

extract

with

heatrecovery:

centralised

Continu

ous

singleroom

supplyand

extract

with

heatrecovery

(continued)

Preparationforinstallation

a.

Aholeofasuitab

ledimensionthroughthefabricofthebuildingwill

berequiredfortheinstallationoftheduct.T

heholewill

needaslight

downwardangle

towardstheoutsidetopreven

twateringress.

b.

Whereductwork


barriermustbem

aintained.T



lesaredrilled.

c.Forceilingmoun

tedfansorterminals/grilles,theholesshouldbecuttothe

minimumrequiredsizesuchthatthefan/grillesp

igotfitssnuglyintothehole.

d.

Itisimportantto


ordinationwitho


designedwithou



Installation

a.

Thefanunitshouldbeinstalledusingthemanufacturerssuppliedor

recommendedfi

xingbrackets.

Acoustic/anti-vibrationisolation

mayberequired.Thiswilld

epe

nd

onthenatureofthemounting

structurerefertothemanufa

cturers

instructions.


42/64



Installationclause

s


2.0Ductwo

rk

Ductinstallation

generalnotes

a.

Ductsshouldbesizedtominimisepressurelossandnoisegeneration.T

hisis

achievedbysizin

goftheductstolimittheairvelocity.

b.

Theroutingofductsshouldaimtominimiseove

rallductlengthand

minimisethenumberofbendsrequired.I

tisparticularlyimportantto

minimisebendsinmainductsoperatingathigherairvelocities.

c.Theneedforpriv

acy(acousticseparation)betweenroomsshouldbe

consideredwhen

planningductlayout.

d.

Whereroomairextractterminals/grillesarenotfittedwithfilters,

considerationshouldbegiventotheneedtoaccessductsforcleaning.

e.

Ductingshouldb


voids(e.g.loftsp



4W/(m.K


condensationforming.W

hereaductextendsexternallyaboverooflevelthe

sectionabovetheroofshouldbeinsulatedoracondensatetrapshouldbe

fittedjustbelow

rooflevel.

Theductsizeandtypespecifiedby

thesystemdesignershouldalw

aysbe

used,tominimisepressureloss

and

noisegeneration.Mainductsshould

berunatthesamesizeasthefan

unitspigot.Ductsizeshouldth

enbe

reducedforbranchducts.

Aradialla

youtmayachieveacoustic

separationmoreeffectivelytha

na

branchedlayout.

Theperformanceoftheventila

tion

systemreliesonefficientair

distributionanditisvitalthatduct

installationisnotleftuntilthelast

momentwhentheonlymeans

of

overcomingobstructionsistoinstall

flexibleductswhererigidductshave

beenspecified.


43/64



Installationclause

s


2.0Ductwo

rk

(continued)

a.

Ductswithinthe

buildingheatedenvelopecarry

ingcoldairbetweenthe

externalsupply/d

ischargeterminalsandthefan

unitshouldbeinsulatedand

wrappedadditio

nallywithavapourbarrierouts

idetheinsulationtoprevent

condensationoc

curringwithintheinsulationmaterial.

b.

Horizontalducting,includingductinginwalls,shouldbearrangedtoslope


intotheproduct.

c.Verticalductingwill


ordertopreventbackflow

ofanymoistureintotheproduct.

d.

Perforatedinsula

tedflexid

uct,usedtominimiseairborneacoustic

transmission,shouldnotbeusedbetweenthefanunitandexternal

dischargetermin

altopreventcondensationocc

urringwithintheinsulation

material.

e.

Whereductwork

penetratesabuildingsairbarrier,identifyonbuilding

drawingsanden

surethatcontinuityofbarrierismaintained.

f.Whereductspas

sthroughfirebarriers,t

heymu

stbeappropriatelyfire

stoppedinaccordancewiththerequirementsofPartBoftheBuilding

Regulations(Fire

safety).

Installationofductsrigid

a.


damaged,forexample

acrossopenloftareaswheretheymaybestood

onorhaveitemsplacedon

them,breakings

ealsandpossiblycrushingtheduct.

b.

Connectionofcomponentsshouldnotresultin

significantairflow

resistance.Componentsshouldbeproprietarya

ndfiteasilytogether

withoutdistortio

n.

c.Rigidductrunsm

ustbeadequatelysupported.

Distortionofrectangularductmay

resultinsignificantreductiono

f

thefreeinternala

reaoftheduct,

increasingtheflowresistanceand

makingsealingmoredifficult.


44/64



Installationclause

s


2.0Ductwo

rk

(continued)

Installationofductsflexible

a.


damaged,forexample

acrossopenloftareaswheretheymaybestood

onorhaveitemsplacedon

them,crushingtheductandrestrictingorpreve

ntingallairflowthroughthe

duct.

b.

Flexibleductshouldbepulledtaughttoensurethatthefullinternaldiameter

isobtainedandfl

owresistanceminimised.T

hisisconsideredtohavebeen

achievediftheductisextendedto90percento

fitsmaximumlength.

c.Flexibleductworkshouldbesupportedatsuitab

leintervalstominimise

sagging.

d.

Bendsinflexibleductshouldhaveaminimumin

sideradiusequaltothe

diameterofthed

uctseeDiagram1.I

ftighterbendsarerequired,r

igid

bendsshouldbe

used.

Itissuggestedthatflexibleducts

shouldbesupportedatintervalsnot

exceeding600mm.

Ductconnections

a.

Allductconnectionsrequiresealing.W

hereduc

tsareinstalledagainsta

solidstructureth

iscanbedifficulttoachieve.In

suchlocationspreassembly

ofductsectionsshouldbeconsidered.T

hiswillrequirethatconnectionsare

permanenttoen

surethesealismaintainedduringinstallation.

b.

Whereaccessto

ductswill

notbepossibleafterconstructioniscomplete,

i.e.w

ithinfloora

ndwallvoids,considerationshouldbegiventopermanent

connectionandsealingwithanappropriatenon

-hardeningsealant,andnot

usingducttapet

oachieveconnectionandsealing.

c.Connectionofle

ngthsofflexibleductmustuse

arigidconnectorandjubilee

clipsorsimilarto

ensurealongtermsealisachie

ved.Connectionsoflengths

offlexibleductshouldnotbetaped-only.


45/64



Installationclause

s


3.0Interna

l

ventilationair

transfer

Airtransfer

a.


hereshouldbean


2in


finish.T

hisisequ


widthdoor.

b.

Ensurethatthea


beenlaid(e.g.ca




fitted,orbya20



f



a.

Freeairmovementbetweenroomsisnotrequiredaseachroomcontains

asingleroomheatrecoveryventilator(SRHRV)u

nit.T

heseunitshavea

balancedsupply

andextractairflowrate.I

tisho

weverrecommendedthat

theprovisionsin

3a.and3b.aremaintainedtom

inimiseanyimbalanceof

flowswithinrooms.

4.0Rooms

upply

andext

ractair

terminals/

grilles

Supplyandextractterminals/grillesgeneralnotes

a.

Allroomairextra

ctterminalsshouldbeinstalled

asdetailedbythesystem

designer.

b.

Roomairextract

terminalsshouldbeinstalledasclosetoceilinglevelas

practical,toensu

rewarmmoistairisremovedfromeachspace.

c.Roomsupplyairterminalsmustnotbelocateda

djacenttowalls,unless

designedtodischargeairawayfromthewall,asthismayresultindown

draughts.

d.

Inopenplanareaswherebothsupplyandextractterminalsmaybeinstalled,

e.g.k

itchendine

rs,t

heterminalsshouldbeadequatelyseparatedtoensure

shortcircuitingis

minimised.

e.

Thenumberand

locationofterminalsinstalledinaspaceshouldensure

effectiveairdistributionandensurethatairnoiseisnotanuisancewhenthe

systemisoperatingatboostairflowrates.


46/64



Installationclause

s


4.0Rooms

upply

andext

ractair

terminals/

grilles

(continued)

Fixedterminalsg

rillesorlouvers

a.

Ifthesupplyand

extractairterminalsarefixed,e

nsurethateffective

balancingofthe

systemcanbeachieved.I

fafac

ilityisnotprovidedwithin

thefanunitthen

dampersshouldbeinstalledw

ithintheductsystemto

allowbalancingwhenthesystemiscommission

ed.

Adjustabletermin

als/grilles

a.

Ensureeachterm

inal/grillecanbelockedinitscommissionedpositiononce

systembalanceh

asbeenachieved.I

tisvitalforthecorrectoperationofthe

systemthatthes

ystemremainsbalancedinitsc

ommissionedstate.

5.0Externa

l

discharge

terminal

MVHR

Externa

l

supplyand

discharge

terminal

Supplyanddischa

rgeterminalsroofandwallmounted

a.

Proprietaryterminalsshouldbeused.

b.

Ensurethatthefreeareaoftheterminalopeningisaminimumof90per

centofthefreea

reaoftheductingbeingused.

c.Thelocationoftheexternaldischargeterminalshouldensurethatthe

potentialforrecirculationofextractairthrough

thesupplyairterminalis

minimised.

Itisrecommendedthatthesup

plyand

extractairterminalsareseparatedby

aminimumof300mmhorizontally

ifplacedonthesamefaadeofa

building.


47/64



Installationclause

s


6.0Controls

Controlsgeneralnotes

a.

Continuousventilationsystemsshouldnotallow

theoccupiertoturnoffthe

fanotherthanatthelocalisolator.Provisionofa

non/offfunctionwill

result

inthefansbeing

operatedintermittentlyandth

erequiredcontinuousair

flowventilationratesnotbeingachieved.

b.

Wheresensorsarenotpre-installedwithinthefanunit,oradditional

optionalsensors

canbeinstalled,onlythesenso

rsspecifiedbythe

manufacturerof

thefanunitshouldbeinstalled

.

c.Ifsensorsareduc

tmounted,t

heirlocationshou

ldbenotedandprovisionfor

accessformaintenanceorreplacementmade.

d.

Ifcontrolofthefanspeedisundertakenmanually,t

heoperationofthefan

inboostmodesh

ouldbemadeobvious.Thiswill

minimisethelikelihoodof

itbeingleftinthismodeunnecessarily.

e.

Humiditycontrolshouldnotbetheonlycontrol

usedinsanitary

accommodation

,whereodouristhemainpollu

tant.

Installationofalternativesenso

rs

mayresultincontrolfunctions

not

performingcorrectly.

Controlslocation

andconfiguration

a.

Installationofmanualcontrolsforthesystemmustmeettherequirements

ofPartMoftheBuildingRegulations.

b.

Installationofroomsensorsshouldfollowthem

anufacturersguidanceon

positioning.

c.Wherecontrolofthefanspeedisundertakenm

anually,switchingshould

beprovidedlocallytothespacesbeingserved,i.e.bathroomsandkitchen.

Provisionofasinglecentrallylocatedswitchisnotsufficientandwill

resultin

fansbeingleftin

inappropriatemodesofoperation.

ApprovedDocumentM,Sectio

n8.3,

recommendsthatswitchessho

uld

belocatedbetween450mmand

1200mmfromfinishedfloorlevel.


48/64



Installationclause

s


7.0Singler

oom

heatrecovery

ventilator

(SRHRV

)

devices

Ventilationofwho

lebuilding

a.

Theseproductsp

rovidebalancedventilationfor

oneroomonly;the

ventilationofallspacesshouldmeettherequire

mentsoftheBuilding

Regulations.


49/64



Recommendedmi

nimumrequirements


1.0System

overvie

w

Visualinspections


a.

Doesthesystem



b.

Isthesysteminst

alledinaccordancewithdesign

criteria?


defectsthatwillbehazardousoraffectthesyste

mperformance?

Initialstart-up

a.

Istheairflowdirectioncorrectateachroomterminal,supplyandextract?

b.

Arethereanyabnormalnoisesonstart-uporwhenthesystemisrunningin

normalbackgrou

ndventilationmode?

Somefanunitshaveastart-up

diagnostic

sequencethatrunsthefansatmaximum

speedforaperiodbeforerevertingtonormal

operationrefertothemanufacturers

operatinginstructions.


50/64



ued)

Minimumrequirem

ents


2.0Commissioning:

airflow

balancingand

measur

ement

Airflowbalancing

a.

Thesystemshouldbebalancedtoensurethatdesignairflowratesare

achievedateach

roomterminal/grille.Asthereareseveralcombinations

ofroomterminal/grilleandfancontrolthatmay

beusedindomestic

systems,thefanmanufacturersinstructionssho

uldbefollowedtoachieve

balancing.I

fspecificdetailsarenotincludedthe

followingprocedureshould

beadopted:

i.

Adjustable

terminalsandafixed(stepp

ed)speedfan.

Thefanspee



Theindexterminalflowrateissettofullyop

enandallotherterminals

areadjusted

toachievetherequiredflowsateachterminal.

Ifthetotalflo

wratecannotbeachievedthroughalltheterminalsthen

thefanspeedshouldbeincreased.

Ifalltheterm

inalshavetobeclosedsignificantlytoachieveonlythe

requiredairfl

owratethenreducethefansp

eedandrebalancethe

terminals.

ii.Adjustable

terminalsandcontrollables

peedfan.

Thefanspee

dshouldbesetapproximatelytoachievethedesired

continuousfl

owrate.


allotherterm



terminal.

Iftheindexterminalhastobeclosedtoachieveonlytherequiredair

flowrate,thenreducethefanspeedandrebalancetheterminals.

Note:Thisistheapprovedp

rocedure

forcommissioningasrequiredbythe


Theindexterminal/grillecanbeassumedto

betheterminalfu

rthestfromthefanunit.


51/64



ued)

Minimumrequirem

ents


2.0Commis

sioning:

airflow

balancingand

measur

ement

(continued)

iii.Fixedterminalswithflowadjustmentb

yductdamperorsimilar

deviceatth

efanunit.

Asi.orii.abo

vedependingonthetypeoffa

nspeedcontrol.

iv.Adjustable

terminalsandfixedvolume

flowfan.

Thefanspee




allotherterm



terminal.Adjustmentoftheterminalsachievesbalancingonly;total

flowrateisg

overnedbythefancontrolsetting.Greatcareshould

betakennot

toclosetheterminalstoofarasthefanunitwill

always

maintainaconstantvolumetricflowrate;closingtheterminalswill

only

requirethefantoworkhardertoachieveagivenairflowrate.

v.Fixedterminalswithautomaticflowad

justmentatthefanunit.

Thefanspee



Theflowsarebalancedbyautomaticdevice

slocatedwithinthefanunit,

andnoadjus

tmentcanbemade.


52/64



ued)

Minimumrequirem

ents


2.0Commis

sioning:

airflow

balancingand

measur

ement

(continued)

Airflowmeasurem

ents

a.

Ensureallinterna


roomsinwhichm


out.

b.

Airflowmeasure


devicewithprop



second(l/s).Refe

renceshouldbemadetodesignairflowrates.

c.Recordtheairflo

wrateateachroomterminalo

nthecommissioning

sheetinSection5,a

longwiththedesignairflow

rateforeachterminal.

Measurementsshouldbetakenatbothmaximu

mrateandminimumrate

fanspeeds.

d.

Itisrecommende

dthatavaneanemometerors

imilardeviceisused

tobalanceandm

easuretheairflowratesateac

hroomterminal.The

instrumentwillrequireahoodtobeattachedto

allowittocoverthe

terminal.

e.

Theinstruments



anaccuracyof

5percent.


a.

Thesupplyande

xtractconfigurationofsomefa

nunitsmayprevent

measurementof

theairflowrates.Insuchcases,ifthemanufacturers

installationinstru

ctionshavebeenfollowedthe

airflowratesspecifiedfor

thatproductmustbeassumedtohavebeenach

ieved.


procedureforairflow

measurementasrequiredb

ythe






n

centre.


53/64



ued)

Recommendedmi

nimumrequirements


3.0Controls

Installation

a.

Ensurealllocalcontrolshavebeeninstalledfollo

wingthemanufacturers

instructions.

b.

Ensurealllocalcontrolsareadequatelylabelled,

indicatingtheirfunction

clearly.

c.Ifsensorshavebeeninstalledseparatelyfromth

efanunit,ensurethe

installationfollow

sthemanufacturersinstructions.

d.

Wherecontrolofthefanisautomated,t

hecontrolsshouldbeconfiguredto

minimisetheocc

urrenceofhunting.

e.

Ifmanualcontrolof,forexample,heatexchang

erby-passisprovided,c